In any multiple-access WDM network using wavelength-tunable receivers, a control channel is required to provide the receiving node with information as to which wavelengths carry the incoming messages. One approach for accomplishing this function uses a common signalling wavelength shared by all nodes. However, this approach requires a second DFB laser to transmit the control headers, substantially increasing the cost of the opto-electronics per node. Moreover, as the number of nodes increases, the density of the control channels grows proportionally creating severe contention for the control channels. Additionally, the data rate of the control channels must increase as the density of the traffic increases, forcing the control channel to transmit in the gigabits/second range. One technique to avoiding these difficulties is the use of subcarrier multiplexed (SCM) headers as the control channels S. F. Su and R. Olshansky, "Performance of WDMA networks with baseband data packets and SCM control channels," Proceedings ECOC '92, pp. 585-588, September 1992. This approach eliminates the need for a second DFB laser at each mode. It also alleviates the control channel contention problem by channelizing the control headers. As such, the control channel data rate is kept low, typically in the 10-100 Mb/s range, making it possible to process the control information with low cost silicon technology. To maximize network throughput, it is desireous for the receiving node to acknowledge and to confirm a successful transmission by the transmitting node. A common wavelength or control channels on subcarriers can be used for acknowledgment. The former approach increases cost per node and the latter increases possible contention between control channels and acknowledgments.